Maximum entropy mapping of IRAS data – III. Evidence for hot dust in M17

• Published in: Monthly notices of the Royal Astronomical Society Vol. 267; no. 1; pp. 141 - 145
• Main Authors: Hobson, M. P., Ward-Thompson, D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford University Press 01-03-1994; Blackwell Science
• Subjects: Astronomy; dust; Earth, ocean, space; Exact sciences and technology; extinction; H II regions; H ii regions. Emission and reflection nebulae; infrared: ISM: continuum; Interstellar medium (ism) and nebulae in milky way; ISM: individual: M17; methods: data analysis; Stellar systems. Galactic and extragalactic objects and systems. The universe; Data analysis; Dusts; Molecular clouds; Stellar formation region; Images; IRAS; Infrared radiation; Interstellar clouds; Maximum entropy method; HII regions
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/267.1.141

A maximum entropy method (MEM) is used to construct an IRAS image of the M17 nebula at 12 μm from the raw IRAS data; no prior information about the structure in the field is given to the maximum entropy routines. The overall emission seen in this image agrees well with that observed at radio wavelengths. The 12-μm flux density of the M17SW region, as measured from the data, suggests the presence of a hot dust component at Td = 108 α 5 K. The distribution of the emission suggests either that the hot dust is mixed with the ionized gas of the H II region, or that it lies in the photo-dissociation region (PDR), and probably represents a population of PAHs. The data are compared with the dust model of Désert, Boulanger & Puget, which confirms that the 12-μm emission is not coming from the denser molecular cloud regions.